Writing article having a capillary reservoir with improved ink delivery

ABSTRACT

A writing instrument having a body, a main reservoir containing ink and housed in said body, a writing head projecting from the front part of said body, and a capillary connector for transferring ink from the main reservoir to the writing head. The instrument has an auxiliary reservoir containing an ink carrier liquid, and an actuator for releasing said liquid from the auxiliary reservoir so that said liquid flows into the main reservoir and expels the ink towards the connector. The carrier liquid contains the ink solvent, in particular water in the case of a water-based ink, and preferably contains all or any of the components of the ink in the main reservoir, whereby the original writing properties of the residual ink carried by the carrier liquid are preserved.

The present invention relates to writing instruments in which ink istrapped in a capillary reservoir. It relates more particularly to awriting instrument of this type with improved ink delivery.

BACKGROUND OF THE INVENTION

In a writing instrument that includes a capillary reservoir, a capillaryconnector transfers ink from the capillary reservoir to the writinghead, which may be either an independent part or the front end portionof the connector. The capillary reservoir usually consists of an arrayof fibers. The fibers may be acetate or polyester fibers, for example.

As the instrument is used, the ink that is consumed from the writinghead is replaced with ink from the capillary reservoir. A major drawbackof that type of instrument is that not all of the ink that is injectedinto the capillary reservoir during fabrication of the instrument isdelivered for writing. It is found that a certain proportion of the inkcontained in the capillary array of the reservoir remains there at theend of the life of the instrument. The proportion of the ink that is notdelivered is generally estimated at around 20%.

This is a drawback in more ways than one. Firstly, the unconsumed inkincreases the cost of the instrument. Secondly, the residual inkpollutes the environment. Finally, the residual ink causes problems withrecycling spent instruments.

OBJECT AND SUMMARY OF THE INVENTION

The aim of the present invention is to overcome the observed drawbacksof writing instruments including a capillary reservoir by improving theink delivery of such instruments.

The above object is entirely achieved by a writing instrument which, inthe manner that is known in the art, comprises a body, a main reservoircontaining ink and housed in said body, a writing head projecting fromthe front part of said body, and a capillary connector for transferringink from the main reservoir to the writing head. Characteristically,according to the invention, said writing instrument also comprises anauxiliary reservoir containing an ink carrier liquid, and actuator meansfor releasing said liquid from the auxiliary reservoir so that saidliquid flows into the main reservoir and expels the ink towards theconnector.

The actuator means are naturally operated by the user on noticing thatthe quality of the writing produced by the instrument is deteriorating.The function of the carrier liquid is to cause ink that is contained inthe capillary array of the reservoir that would not migrate naturallyduring normal use of the instrument to be displaced towards theconnector. The ink carried by the carrier liquid reaches the connectorand the instrument can continue to be used until all of the ink isconsumed.

The carrier liquid providing the above function preferably contains theink solvent. In particular it contains water in the case of awater-based ink.

The carrier liquid injected into the main reservoir displaces theresidual ink remaining in said reservoir, but may degrade the originalwriting characteristics of the ink on mixing therewith. To overcome thisproblem, it is preferable for the carrier liquid to contain all or anyof the ink components that confer its writing properties upon the inkand whose presence in the carrier liquid allows the original writingproperties of the residual ink mixed with the carrier liquid to bepreserved.

For example, in the case of a writing instrument using water-based ink,the carrier liquid contains a certain proportion of glycol, inparticular of the order of 20% to 30% glycol, which is used in the artto increase the solubility in water of certain constituents of awater-based ink.

For example, in the case of a writing instrument using a dry-wipe ink,the carrier liquid contains a resin used in the art to confer itsdry-wipe property on the ink.

The carrier liquid may contain additives promoting its operation, inparticular surfactants.

In one embodiment, the auxiliary reservoir is also made of fibrousmaterial; when the actuator means are operated, the auxiliary reservoiris placed in contact with the rear portion of the main reservoir.

In this variant, the main and auxiliary reservoirs are preferably bothdisposed in the body of the instrument in the same longitudinaldirection. The front face of the auxiliary reservoir is thereforeapplied to the rear face of the main reservoir when they are broughtinto contact. The carrier liquid contained in the auxiliary reservoirdiffuses by capillarity into the main reservoir when they are broughtinto contact.

Preferably, the capillarity of the auxiliary reservoir is lower thanthat of the main reservoir. The advantage of this is that it facilitatesstarting the transfer of carrier liquid from the auxiliary reservoir tothe main reservoir when they are brought into contact.

In a different embodiment, the auxiliary reservoir is formed of a spongymass impregnated with the carrier liquid. When the actuator means areoperated, the spongy mass is compressed, thereby releasing the carrierliquid that it contains.

In a further embodiment, the carrier liquid is in the liquid state inthe auxiliary reservoir. The instrument comprises means for opening saidauxiliary reservoir to release the carrier liquid contained therein whenthe actuator means are operated.

From a structural point of view, the auxiliary reservoir, of whateverkind, is accommodated in an actuator member that is adapted to sliderelative to the portion of the body of the instrument containing themain reservoir, the connector and the writing head, for example. Notethat the displacement of this actuator member initiating release of thecarrier liquid is reflected in a reduction in the length of theinstrument, which has the advantage of allowing users to tell at aglance that the auxiliary reservoir has been actuated.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood on reading the followingnon-exhaustive description of embodiments of writing instruments withimproved ink delivery, which description is illustrated by the appendeddrawing, in which:

FIGS. 1 to 4 show diagrammatically four steps of the main operation ofthe instrument, and

FIGS. 5 and 6 are diagrammatic fragmentary views in longitudinal sectionof an instrument with main and auxiliary fibrous reservoirs, theauxiliary reservoir being slideably mounted in a rear portion of thebody of the instrument and shown in an inactive position in FIG. 5 andin an active position in FIG. 6. FIG. 7 shows the relation of thecomponents at the rear of the instrument.

MORE DETAILED DESCRIPTION

The user realizes that the writing instrument being used is running outon noticing a reduction in the intensity of the color of the writing, asis caused by a relative reduction in the flow of ink from the reservoir.This applies in particular with writing instruments in which the ink istrapped in a capillary reservoir, especially a fibrous reservoir. Atpresent, on noticing this, the user has no option but to discard theinstrument, possibly once some minimum acceptable color intensity isreached.

It is found that under these extreme conditions the capillary reservoirstill contains ink that is trapped in the fibrous array and that is notdelivered for the purposes of writing during normal use of theinstrument.

The present invention improves the ink delivery of the instrument byusing a carrier liquid to expel the residual ink contained in thecapillary reservoir until virtually all of the ink has been consumed,the carrier liquid being released by the user operating actuator meanson noticing that the writing is of reduced color intensity.

The auxiliary reservoir containing the carrier liquid thereforeco-operates with an actuator member that has an inactive position innormal use of the instrument, and an active position that releases thecarrier liquid. In the inactive position, ink is transferred from themain reservoir to the writing head, and in the active position thecarrier liquid contained in the auxiliary reservoir is transferred tothe main reservoir to expel the residual ink that it still contains, sothat the ink goes towards the connector.

FIGS. 1 to 4 show this general principle that is characteristic of theinvention in one particular embodiment of the invention.

This embodiment of the invention consists in a writing instrument 1 thatcomprises a body 2, a main reservoir 3 and a transfer tip 4 that has anend that projects beyond the front portion 2 a of the body 2 and servesas a writing head 5.

The body 2 of the instrument has a rear part 7 adapted to slide relativeto the main part 8 of the body 2. This rear part 7, which constitutesthe actuator part characteristic of the invention, provides a housingfor an auxiliary reservoir 6. In the embodiment shown here, the rearpart 7 has an outside diameter that is chosen in relation to the insidediameter of the main part 8 so that, when it slides, the rear part 7penetrates into the space inside the main part 8 whilst maintaining aseal.

The main reservoir 3 contains writing ink suitable for the instrument 1.The auxiliary reservoir contains a carrier liquid adapted to migrate bycapillary action into the main reservoir and to expel residual inkcontained therein towards the transfer point 4. This carrier liquidcontains the ink solvent, which is water in the case of a water-basedink, and various additives, in particular surfactants adapted to promotethe flow of ink upon migration of said liquid into the main reservoir.

The two reservoirs 3, 6 are both made from a fibrous material in theconventional way.

The transfer tip 4, whose front end constitutes the writing head 5, hasa rear end 4 a that penetrates into the fibers of the front portion ofthe main reservoir 3.

FIG. 1 shows the respective positions of the main reservoir 3 and theauxiliary reservoir 6 during normal use of the instrument. The tworeservoirs are at a distance from each other; in particular, a system oftongues 9 pushes the auxiliary reservoir 6 towards the rear end of therear part 7, preventing said auxiliary reservoir 6 from coming intocontact with the main reservoir 3, in particular when the instrument 1is in a position such that the tip is at the bottom.

Ink consumed by the writing head 5 during use of the instrument 1 isreplaced by ink contained in the main reservoir 3 and transferred by thetransfer tip 4 to the writing head 5. When the greater part of the inkcontained in the reservoir 3 has been consumed, a reduction in thequantity of ink reaching the writing medium causes the user to noticethat the quality of the writing is deteriorating. FIG. 2 shows thisparticular stage of the use of the instrument, the number of shadinglines on the main reservoir 3 and the transfer tip 4 showing that acertain quantity of ink remains in the main reservoir but isinsufficient to achieve good writing quality. This tells the user toactivate the auxiliary reservoir 6.

This is achieved simply by applying pressure to the rear end 7 a of therear part 7 of the body 2 so as to move this rear part 7 in thedirection of the arrow F, said rear part 7 entering partly into thespace inside the main part B. During this displacement, the front face 6a of the auxiliary reservoir 6 comes into contact with the rear face 3 aof the main reservoir 3. The carrier liquid contained in the auxiliaryreservoir 6 migrates into the main reservoir 3, as a result of capillaryaction, and expels the residual ink that it contains towards thetransfer tip 4, and thus towards the writing head 5. To optimize thiscapillary diffusion of the carrier liquid, it is preferable if thecapillarity of the main reservoir 3 is higher than that of the auxiliaryreservoir 6; providing this difference in capillarity is a simple way toovercome any barrier that might be imposed by the interface between thetwo reservoirs 6, 3. In the case of a fibrous reservoir, this kind ofdifference in capillarity may be obtained by reducing the density of thefibers in the auxiliary reservoir compared to that of the mainreservoir, for example. The auxiliary reservoir 6 preferably has a fiberdensity that is 80% to 95% of the fiber density of the main reservoir.For example, in a marker, with the fiber density of the main reservoirbeing of the order of 0.23 grams per cubic centimeter (g/cm³), a fiberdensity of the order of 0.20 g/cm³ is chosen for the auxiliaryreservoir.

Accordingly, because of the contact between two reservoirs 3, 6, it isagain possible to use the writing instrument 1 under normal conditions,but only for a limited time period that depends on the residual quantityof ink in the main reservoir 3.

FIG. 3 shows this continued use, involving transfer of the carrierliquid from the auxiliary reservoir 6 to the main reservoir 3, and FIG.4 shows the instrument 1 at the end of its life, when all of the ink hasbeen consumed and the instrument must therefore be discarded.

The quantity of carrier liquid contained in the auxiliary reservoir 6must be just sufficient to expel the residual quantity of ink containedin the main reservoir 3, which on average is of the order of 20% to 40%of the original quantity of ink injected into said main reservoir 3(depending on the type of ink used).

In this case, the quantity of carrier liquid in the auxiliary reservoir6 is preferably of the order of 20% to 40% of the quantity of ink in themain reservoir of the instrument.

Independently of this option for temporarily prolonging the service lifeof the instrument by consuming residual ink contained in the mainreservoir 3, the actuation of the rear part 7 causes a deformation ofthe body of the instrument 1 that shows a user that said instrument isin its final phase of use, with no possibility of further extension ofits useful life. This actuation, i.e. the depression of the rear part 7into the main part 8 of the body 2, reduces the length of the body 2 ofthe instrument 1. Information is provided, where applicable on the bodyof the instrument, to advise the user of the active and inactivepositions of the rear part 7 and that it is important to obtain areplacement instrument once the rear part 7 has been moved to the activeposition.

Clearly, the body 2 of the instrument must be equipped with means forholding the rear part 7 in the inactive position during normal use, thenactuating it and finally retaining it in the inward position.

FIGS. 5 and 6 show one particular arrangement for retaining the rearpart 7 relative to the main part 8 of the body 2 in this way.

The rear part 7, which is generally cylindrical, is closed off by a rearend 7 a and open at its other end for inserting the auxiliary reservoir6. Near its open end, the rear part 7 has an annular shoulder 14 ofsubstantially frustoconical shape on its outside periphery, with theinclined surface facing towards the front end of the instrument. Themain part 8 of the body 2 has four annular shoulders 10 to 13 on itsinside periphery of which a first shoulder and a fourth shoulder formdefinitive abutments and a second shoulder and a third shoulder, havinga frustoconical shape complementary to that of the shoulder carried bythe actuator part, form temporary abutments. The first shoulder 10extends towards the interior of the instrument from the edge 8 a at theend of the main part 8. The second shoulder 11 is at a small distancefrom the first shoulder 10 and has a frustoconical shape complementaryto that of the shoulder 14 on the rear part 7. To be more precise, andas is clear from FIG. 5, the shoulder 14 of the rear part 7 is disposedbetween the first two shoulders 10, 11, with the inclined surface of theshoulder 14 of the rear part 7 pressed against the inclined face of thesecond shoulder 11 of the main part 8. In the inactive position shown inFIG. 5, the shoulder 14 of the rear part 7 is temporarily immobilizedbetween the first two shoulders 10, 11 on the main part 8. However,because of the complementary shape of the shoulders 14 and 11 and thedeformability of the materials used, it is sufficient to apply adequatepressure to the rear end 7 a of the part 7 to force the shoulder 14 onthe rear part 7 beyond the second shoulder 11 of the main part 8 andmove the rear part 7 relative to the main part 8.

The third shoulder on the main part 8 has the same configuration as thesecond shoulder 11. Similarly, the fourth shoulder 13 has the sameconfiguration as the first shoulder 10. Accordingly, on displacement ofthe rear part 7, the shoulder 14 on the rear part 7 is stopped at thethird shoulder on the main part 12, but it is again sufficient for theuser to exert adequate pressure for it to overcome this obstacle andcome into final abutting engagement with the fourth shoulder 13. Thisfinal position, which corresponds to the active position of theauxiliary reservoir 6, is shown in FIG. 6, with the shoulder 14 on therear part 7 inextricably trapped between the third and fourth shoulders12, 13 on the main part 8.

The distance traveled by the shoulder 14 between the inactive position(FIG. 5) and the active position (FIG. 6) is determined so that, in theactive position, the front face 6 a of the auxiliary reservoir 6penetrates approximately 1 millimeter (mm) into the rear face 3 a of themain reservoir 3 to allow the transfer of the carrier liquid from thereservoir 6 to the reservoir 3 and also to provide a visual indicationof the final stage in the use of the instrument.

To attach the reservoir 6 to the rear end 7 a of the rear part 7 duringnormal use of the instrument 1, a tongue 9 on the inside face of thepart 7 is pressed onto the front face 6 a during displacement of therear part 7 and is pushed back by the main reservoir 3 so that it doesnot prevent contact between the two reservoirs 3, 6.

Of course, this is not the only feasible embodiment of the invention. Itis possible to envisage other ways of immobilizing the rear body 7relative to the main body 8 and other modes of displacement, for examplea displacement that is not merely longitudinal but also involvesturning, and is achieved by providing on the inside periphery of themain part 8 a helicoidal groove 8 b so that the rear part 7 is screwedin, as it were, so that it penetrates into the main part 8, thehelicoidal groove being provided with non-return means 8 c similar tothe frustoconical shoulders of complementary shape.

In the case of two fibrous material reservoirs 3, 6, the diameter of themain reservoir 3 is preferably greater than that of the auxiliaryreservoir 6. This ensures that the whole of the front face 6 a of theauxiliary reservoir 6 is pressed against the rear face 3 a of the mainreservoir 3, even if the relative centering of the two reservoirs isless than perfect.

In one particular non-limiting embodiment of the invention, the mainreservoir 3 had a diameter of 13.3 mm, a length of 37 mm, contained 3grams (g) of ink, and had a fiber density of 0.234 g/cm³. The auxiliaryreservoir 6 had a diameter of 11.4 mm, a length of 29 mm, contained 1.5g of carrier liquid, and had a fiber density of 0.23 g/cm³.

The auxiliary reservoir may be a capillary reservoir withoutconstituting a fibrous reservoir, for example a reservoir made fromsintered powder, or it may consist of a spongy mass that has absorbed acertain quantity of ink that can be delivered by compressing said spongymass. In this case, the relative displacement of the rear part 7 must beover a sufficient distance to obtain the required compression effect.

The auxiliary reservoir may equally consist of a sachet containingliquid ink. In this case the actuator part, which may be the rear part7, must be provided with means for opening said sachet, for example oneor more tapered lugs which, on relative displacement of said parts,pierce the sachet to allow the carrier liquid that it contains to flowout. This sachet is located towards the back of the rear part and isheld against the rear face 3 a of the main reservoir 3.

In all the examples given above, the actuator part is displaceable inlongitudinal translation in the direction of the axis of symmetry of theinstrument 1. This is not the only implementation of the invention,however. For example, in the case of an auxiliary reservoir taking theform of a spongy mass containing the carrier liquid, the actuator partmay consist of a portion of the body of the instrument containing theauxiliary reservoir and made from a material that is deformable bycompressing it or twisting it, and whose deformation is preferablypermanent. It is then sufficient for the user to apply adequate force tothis portion of the instrument to deform it and thereby compress thefibrous or spongy mass, releasing the carrier liquid from the auxiliaryreservoir. In this case it is the mechanical deformation of this portionof the body of the instrument that provides the visual indication of theend of life of the instrument.

1. A writing instrument comprising a body, a main reservoir containingink and housed in said body, a writing head projecting from a front partof said body, and a capillary connector for transferring ink from themain reservoir to the writing head, wherein said writing instrument alsocomprises an auxiliary reservoir containing an ink carrier liquid, andactuator means for releasing said liquid from the auxiliary reservoir sothat said liquid flows into the main reservoir and expels the inktowards the connector, wherein the main reservoir and the auxiliaryreservoir are both fibrous material reservoirs and wherein, uponoperations of the actuator means, the auxiliary reservoir is displacedinto contact with the main reservoir.
 2. A writing instrument accordingto claim 1, wherein said carrier liquid contains ink solvent.
 3. Awriting instrument according to claim 2, wherein said ink is water-basedand said ink solvent is water.
 4. A writing instrument according toclaim 1, wherein said ink comprises multiple components, and saidcarrier liquid contains all or any of the components of the ink in themain reservoir, whereby the original writing properties of the residualink carried by the carrier liquid are preserved.
 5. A writing instrumentaccording to claim 4, of water-based ink type, wherein the carrierliquid contains glycol.
 6. A writing instrument according to claim 4, ofdry-wipe ink type, wherein the carrier liquid contains a resinconferring its dry-wipe properties on the ink.
 7. A writing instrumentaccording to claim 1, wherein the carrier liquid contains at least onesurfactant.
 8. A writing instrument according to claim 1, wherein thequantity of carrier liquid is of the order of 20% to 40% of the quantityof ink contained in the main reservoir.
 9. A writing instrumentaccording to claim 1, wherein the main reservoir and the auxiliaryreservoir are disposed in the body of the instrument in the samelongitudinal direction and wherein the auxiliary reservoir has a frontface pressed onto a rear face of the main reservoir when they arebrought into contact.
 10. A writing instrument according to claim 1,wherein the auxiliary reservoir has capillarity lower than the mainreservoir.
 11. A writing instrument according to claim 10, wherein thefiber density of the auxiliary reservoir is from 80% to 95% of the fiberdensity of the main reservoir.
 12. A writing instrument according toclaim 1, wherein the diameter of the main reservoir is greater than thediameter of the auxiliary reservoir.
 13. A writing instrument accordingto claim 1, wherein the auxiliary reservoir is housed in an actuatorpart that is a rear part mounted to slide relative to the body of theinstrument containing the main reservoir, the capillary transfer meansand the writing head.
 14. A writing instrument according to claim 13,wherein the body of the instrument comprises means for retaining theactuator part adapted to retain it temporarily in an inactive positionand, upon operation of said actuator part, to move it to an activeposition and to retain it inextricably in said active position.
 15. Awriting instrument according to claim 14, wherein the means forretaining the actuator part comprise: a) a substantially frustoconicalannular shoulder on an outside periphery of the actuator part, and b) onan inside periphery of the main part of the body, facing said shoulder,four annular shoulders, of which a first shoulder and a fourth shoulderform definitive abutments and a second shoulder and a third shoulder,having a frustoconical shape complementary to that of the shouldercarried by the actuator part, form temporary abutments.
 16. A writinginstrument according to claim 14, wherein the actuator part undergoeslongitudinal and rotational displacement by virtue of a helicoidalgroove provided on the inside periphery of the main part, allowing theactuator part to penetrate into the main part, said groove beingprovided with non-return means.